1. Field of the Invention
The present invention relates to a catheter including a catheter body including a coil.
2. Description of the Related Art
Catheters have been used while being inserted into tubes and body tissues of human bodies, such as vessels, alimentary canals, ureters, etc. A catheter known as one type of such catheters includes a catheter body including a coil, the coil formed such that a plurality of metal strands are wound or stranded (see Japanese Unexamined Patent Application Publication Nos. 2005-296078 or 2006-174959). In the catheter, the coil of the catheter body may be coated with resin and include a cylindrical resin tip at the distal end (distal point) of the catheter. The tip has a tapered section. (For example, see US Patent Application Publication No. 2007/0208368.)
Since the catheter includes the catheter body including the coil, good torque transmission performance is provided. For example, the catheter has been preferably used for an operation of dilating a stenosis, in particular, a substantially completely occluded stenosis or an occlusion of a vessel, and allowing blood to flow therethrough.
The catheter, in which the catheter body includes the coil coated with resin and the tapered resin tip is provided at the distal end of the catheter, has been preferably used to pass through a vessel called a collateral channel, in controlled antegrade and retrograde tracking (CART) approach, which is a new operation in cardiac catheter treatment applied to a lesion of a severe stenosis called a chronic total occlusion (CTO).
The diameter of the collateral channel may be small. In addition, the collateral channel may have a branch at an acute branching angle of 90° or smaller with respect to a main vessel. The tapered resin tip at the distal end of the catheter can enter the branch at an acute angle without damaging an inner surface of the vessel. The catheter body including the coil provides high torque transmission performance. Thus, the catheter can be smoothly advanced through the collateral channel including the branch while the catheter dilates the collateral channel.